Pollux

If you know basic biology -- or if you've read or watched just about any science fiction over the last half-century -- then you know that life on Earth is carbon based. That means that the chemistry of life is based on carbon atoms. They bond easily with other atoms, such as oxygen and nitrogen, and the compounds they make are both stable enough and flexible enough to support the processes of life.

One of the best-known stars in the night sky is busily making carbon right now, along with another vital ingredient for life, oxygen. The atoms are being forged deep inside the star's core.

Pollux is one of the "twins" of Gemini. It's half-way up the western sky at nightfall, to the left of the other twin, Castor. Pollux is the brighter of the two, and shows a distinctly orange color.

That color helps tell us that Pollux is in the final stages of life. It's consumed the original hydrogen in its core to make helium. Now, it's fusing the helium to make heavier elements -- carbon and oxygen. The changes have caused its outer layers to puff up and get cooler, so they look orange.

Eventually, Pollux will cast its outer layers into space. Most of those layers will consist of hydrogen and helium. But they'll also contain carbon and oxygen. In the distant future, some of these atoms may be incorporated into new stars and planets, and perhaps new life -- life based on carbon -- an element forged in the hearts of stars.

We'll talk about Castor tomorrow.

Script by Damond Benningfield, Copyright 2011

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